A Routing Algorithm for Underwater Acoustic– Optical Hybrid Wireless Sensor Networks Based on Intelligent Ant Colony Optimization and Energy-Flexible Global Optimal Path Selection

Due to the increasing demand for oceanic exploration, routing algorithms in Underwater Wireless Sensor Networks (UWSNs) have garnered widespread research interest. However, the majority of current routing algorithms only utilize a single transmission medium and consider the information from merely one or two hops when selecting relay nodes, thereby attaining limited achievement of globally optimal path selection. To address these issues, in this paper, we propose a routing algorithm for underwater acoustic-optical hybrid wireless sensor networks based on Intelligent Ant-colony-optimization and Energy-Flexible global optimal path selection (named as IAEF). Given the diverse energy-consumption characteristics of acoustic and optical waves, the proposed IAEF algorithm employs acoustic waves in seeking optimal path and optical waves in delivering data packets. In contrast to other routing algorithms based on ant-colony techniques, the proposed IAEF algorithm enables source nodes to select the optimal path for data transmission with the heuristic factor updated according to a comprehensive consideration on remained energy and transmission deviation angle. Considering the limited energy in networks, the proposed IAEF algorithm designs an energy classification network update mechanism with flexible cycles, which enables network updates according to an adjustable energy threshold for the nodes along the optimal path. Additionally, a protection period is implemented to prevent excessive network updates to improve Packet Delivery Rate (PDR) and network lifetime. Simulation results exhibit that the proposed IAEF algorithm can obtain up to about 37% and 78% improvements in PDR and network lifetime when compared to the classical routing algorithms adopted in the simulations.